package com.atguigu.distributed.lock.juc;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.atomic.AtomicStampedReference;

public class ABADemo {
    static AtomicReference<Integer> atomicReference = new AtomicReference<>(100);
    static AtomicStampedReference<Integer> atomicStampedReference = new AtomicStampedReference<>(100,1);

    public static void main(String[] args) {
        System.out.println("========以下是ABA问题的产生=========");
         new Thread(() -> {
             atomicReference.compareAndSet(100,101);
             atomicReference.compareAndSet(101,100);
         },"t1").start();
         new Thread(()->{
             try {
                 TimeUnit.SECONDS.sleep(1);
             }catch (Exception e){
                 e.printStackTrace();
             }
             System.out.println(atomicReference.compareAndSet(100,2019)+"\t"+atomicReference.get());
         },"t2").start();
         //暂停一会线程
        try {
            TimeUnit.SECONDS.sleep(2);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("========以下是ABA问题的解决=========");
        new Thread(()->{
            int stamp = atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName()+"\t第1次版本号:"+atomicStampedReference.getStamp());
            try {
                TimeUnit.SECONDS.sleep(1);
            }catch (Exception e){
                e.printStackTrace();
            }
            atomicStampedReference.compareAndSet(100,101,
                    atomicStampedReference.getStamp(),atomicStampedReference.getStamp()+1);
            System.out.println(Thread.currentThread().getName()+"\t第2次版本号:"+atomicStampedReference.getStamp());
            atomicStampedReference.compareAndSet(101,100,
                    atomicStampedReference.getStamp(),atomicStampedReference.getStamp()+1);
            System.out.println(Thread.currentThread().getName()+"\t第3次版本号:"+atomicStampedReference.getStamp());

        },"t3").start();
        new Thread(()->{
            int stamp = atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName()+"\t第1次版本号:"+stamp);
            try {
                TimeUnit.SECONDS.sleep(3);
            }catch (Exception e){
                e.printStackTrace();
            }
            boolean result = atomicStampedReference.compareAndSet(100, 2019,
                    stamp, stamp + 1);
            System.out.println(Thread.currentThread().getName()+"\t修改成功否："+result+"\t当前最新实际版本号："+atomicStampedReference.getStamp());

            System.out.println(Thread.currentThread().getName()+"\t当前实际最新值："+atomicStampedReference.getReference());
        },"t4").start();
    }
}
